That's just going to be a really different from the shopping experience customer's are used to today, and I don't think customers would go for it. I know for at company asking customers to pay for the shopping experience would be a non-starter... If bot traffic became untenable we would probably do something like required account creation + sms verification, and even that would be a huge change in expectations for our customers.
Well it sounds like it’s either that or tragedy of the commons where Amazon et al needs to charge higher and higher prices due to inefficient bots constantly crawling their site. Also consumers are already about to change how they shop. In 3 years nobody will be firing up the browser to go to Amazon.com. They will be asking an agent to “buy the cheapest 3 ply toilet paper from a brand name and some decent flossers. Spend no more than $30 total.” For this kind of shopping the cost of the search is built into the purchase price one way or another.